U.S. Pat. No. 4,513,268 entitled "Automated Q-Line Circuit Breaker" describes a molded case residential circuit breaker employing a thermal-magnetic trip unit to automatically sense overcurrent circuit conditions and to automatically interrupt circuit current accordingly. The thermal-magnetic trip unit electrically connects with the movable contact arm by means of a braided electrical conductor to provide movable electrical connection. When the circuit breaker is subjected to overcurrent conditions or repeated circuit interruption under test circuit conditions, mechanical stress is exerted upon the welded connection between the end of the braid conductor and the movable contact arm. When the circuit breaker is designed for higher ampere interruption, such as within industrial applications, some means must be employed to reduce the strain exerted upon the welded connection between the movable braid conductor and the movable contact arm.
Thus, one purpose of the invention is to provide strain relief to the welded connection between the circuit breaker movable contact arm and the braid conductor. It is well appreciated in the electric circuit protection field that the latching surfaces within circuit breakers must be carefully machined and lubricated in order to ensure repeated latching and unlatching between the surfaces over long periods of continuous use. When such circuit breakers are rated for industrial applications, it would be economically advantageous to manufacture such latching surfaces without the requirements of extensive machining and polishing operations.
It is accordingly a further purpose of the invention to provide such latching surfaces without requiring machining or polishing while maintaining repeated interruptions over long periods of continued use at higher rated currents.